Repeater circuits



Jan. 0, 1925. 1,523,473

A. B. CLARK 'REPEATBR CIRCUITS I Filed Sept. 28, 1922 A, 4, mm1

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Pat nted Jaazo, 1925,

To (ZZZ it may concern 'Be it known that LALvA B. Cranial residinw'.'at Brooklyn, in the county of Kings and tate of New York, have invented certain Improvements inRepeater Circuits, of

which the :following is a specification.

This invention relatesto improvements in stood from the a,

repeatercircuits.

Informer repeater circuit arrangements, in -which'-'the repeater elements 4 comprisethe well known vacuum tube, it has,been i the practice to supply the space current for the output circuit of the tube either by bridging'a battery-having a retardationcoil in series thereivith from one side of the out put circuit to ground or by connecting a'bat in series with the output transformer to the plate. With the space battery and re tardation coil bridged across the output circuit to; ground, it was necessary to make .the impedance of; the retardation coil relatively hi'gh's'o that'it'would not shunt out the lower frequencies. With the space battery in series fwith ih'eoutput transformer there would 5 be a Ftendency-fOr cross-talk to occur when several-output circuits were supplied with current from the same battery. In the arrangements of-this invention the space curr'ent'for the-output circuit is supplied from a battery and a relay winding in series with the output transformer and with a condenser in bridge from apoint. between the relay and'output transformer to the filament or ground. Such an arrangement presents several' distinct advantages'over prior arrange ,vments i" As-the-space battery is in series in the output-circuit rather than in shunt across said-circuits retardation coil of relatively high impedance-is notv necessary and the 40 windingof -relatively cheap relay or retardation coil may be substituted therefore and result in a considerable reduction in expenditure. -With a condenser shunt around the space battery and relay the alternating current ath of the outputcircuit does not include t e battery and relay winding. This obviates cross-talk and also introduces less transmission loss particularly at low frequencies. The contacts of the relay substituted for the retardation coil in accordance with the invention are utilized to control an alarm circuit whereby an indication may-be given'should the space current of a tube fail. As the space current is dependent upon 6 the filament current this same alarm circuit .XAN EELEG APH' COMPANY, a conronarxo'n or NEW,YQRK.

' aEPEA'rER omoui'rs h i j v Application filed September 2 8, Serial No.. 591 ,1{52.

-tau give" an indictmenor"; failure o ffttliei features of the invention 'wil after plied Ito the main" OF BROOKLYN, "NEW YORK, n-ssrenoR-ro mien: runni'iioii filament current and special'appamtus :fons; this urpose may be done away with; Other 1 G I appeaflmore fully from the detaileddcscription hereinagfiof given. a

The invention may be more fully under--12 owing description r'to -v- 'gether with the accompanying drawing dim the Figures 1' and 20f which the inventionuisfii illustrated, Fig. 1 shows a plurality of one. f way repeater circuits embodying the inreni, tion, while-in Fig. 2 the'invention is-sho'wn? in a two way two element repeatercircuits-ax; In Fig. l are shown two one way-.repaten. 7 circuits L ancl-L 'which include 'astthe repeater elements the v'acui'nn' tubes;- R 1. and R which are of a' Wpei-welh-luiowx'r -in the art'and inclndea grid, a filament-, 1

and a plate elcctrode.f Potential is nap-i late "of tube R, from" the hate: tery 1 m the; follow-ing manner: :from. ground, battery 1, winding of relay 2,w'mding of transformer 3, to the plate; 'Between :14 the winding of relay Q'and winding of tranm former 3 is a condenser 4 bridgedeitherto ground or to the filament as'shownm With this arrangement the" alternating current path'in the output -ol the tube will he asfdllows i from the filament, through condenser: 4. winding of transtm'mer B, to'the. plate and. filament. It is pointed out'that'lhis alter; nating current path-does not includewtlio plate battery 1 nor the winding OfiIQl-BY!2 and hence less transmission losswill berinau troduced ,.than in former arrangement-ti Furthermore as the alternating current-does not pass through .battery '1 therewill 'be less tendency for cross-talk to =exist when otheit repeaters, such asR are supplied withplatfi..9- potential from lial to'r tube R is supplied asfollows-zffrom ground, battery 1, windingof relay 5. wind- 4 ing of transformer .6, to the-plate flfiifitlhfii? R Between the winding of relay .5- and '1 the winding of transformer 6 isa-a condenser 7 bridged to round or to thefilament-"as shown. The alternating current pathin the output of tube R, is then as follows: from the filament of tube R condenser 7, windingof transformer 6, to the plate of R and hence does not traverse the battery 1 or. winding of relay 5. The windings of relays 2 and 5 should be of high enough impedance to prevent cross-talk betweenthe circuits.

battery The plate'pQten-g However, this impedance is not as high as is needed in the retardation coils utilized in former arrangements and hence a relatively inexpensive relay may be utilized in this connection and the expense of the retarda-- tion coils done away with. The relays 2 and alarm to give an indication of t 18121111111, of-

the current. Failure of the filament current interrupts the space current and thus also gives an alarm.

In Fig. 2 the arrangements of the invention are shown embodied in a two-way twoelement repeater circuit. In this arra ement a common batter supply is-provi ed for the filaments, gri s, and plates and a detailed description thereof is given in a Patent No. 1,436,683, issued November 28, 1922, in the name of A. F. Rose. The arrangements comprise the vacuum tubes R, and It, which are of a type well known in the art. These tubes interconnect the line sections L and L, with which are associated the balanci network N and N Associated with ines L, and L are the usual three winding transformers 12 and 11. The

out ut circuit 14 of tube R, is associated witi a winding of transformer 12 and the out at circuit 13 of tube R is associated with a winding-of transformer 11. The output circuits of the tubes may include the filters F, and F The input circuits of the tubes may include the otentiometers 17 and 18. A common battery source 20 is provided for heatingthe filaments. Potential is applied to the rids from the common buttery source 21. oten'tialis appliedto the plate of tube R over the following circuit:

- from groundand battery 19, conductors 34 and 35, winding of relay 33, conductor 37, winding of transformer 12, filter F conductor 40, to the plateof tube R At a point between winding of relay 33 and-the winding of transformer 12 isu circuit bridged to the filament of tube R This bridged circuit includes the condenser 15. Accordingly the alternating current path in the output of the tube It, will benas follows: from the plate, conductor 40, filter F winding of transformer 12, condenser 15, to the filament of the tube R The alternating current accordingly will not traverse the plate battery nor the winding of relay 33. Potentery 19, conductors 34 and 36, winding of relay 32, conductor 38, winding of transformer 11, filter F conductor 39, to plate of R At a point between winding of relay 32' and winding of transformerll is a eircuitbridg'ed to the filament of. tube 3,.

This bridgedcircuit includes the condenser 16. .A ccordingly the alternating current ath m the output of tube R, will'be as ollows:' from the plate, conductor 39, filter F winding of transformer 11, condenser 16.

t0 the filament. The alternating current accordingly will not traverse the plate battery nor the winding of relay 32. Relays 32 and 33 serve to control an alarm circuit com rising their armatures and contacts, con uctors 41 and 42, conductor 43, alarm device 45 and battery 44. Whenever the plate orfilament current fails these relays will be deenergized and close the alarm circuit to give an indication of the current 7 failure.

While the invention has been disclosedin '4 certain specific arrangements which are deemed desirable, it is understood that it is' capable of embodiment in manyand widely varied forms without departing from the spirit of the inventionas defined by the apto said output circuits at points between said-condensers and transformers and terminating in a common battery, andjrelay" windings in said circuits.

2. A plurality of repeater circuits, each circuit including a vacuum tube havi ment and plate electrodes, the output circuit of each tube comprising a condenser and a. transformer winding serially connected between filament and plate, circuits connectedto said output circuits at points between,

said condensers and transformers and ter minating in a common battery, relay w ndings in said circuits, and alarm circuits co'n'= trolled by the contacts of saidrelays.

In testimony whereof, I have signed'my name to this specification this 27thday .of'

September, 1922.

ALVA autumn,"

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